Ad serving describes the technology and service that places advertisements on web sites. Ad serving technology companies provide software and/or services to web sites and advertisers to serve ads, count them, choose the ads that will make the website the most money or the advertiser the best return, and monitor progress of different advertising campaigns.
Ad servers come in two flavors: local ad servers and third-party or remote ad servers. Local ad servers are typically run by a single publisher and serve ads to that publisher's domains, allowing fine-grained creative, formatting, and content control by that publisher. Remote ad servers can serve ads across domains owned by multiple publishers. They deliver the ads from one central source so that advertisers and publishers can track the distribution of their online advertisements, and have one location for controlling the rotation and distribution of their advertisements across the web.
Behavioral targeting is currently implemented in the art by using cookies to track the pages that a browser visits on the Internet and using this information to place the browser user into defined segments. These segment assignments are then used to target ads to that browser. This requires that the browser has a cookie and has been seen online before the ad call is made. Since the browser has to be seen online at some point before the ad request, behavioral targeting is limited by the number of sites that participate in the page tracking.
Contextual targeting is currently implemented in the art by passing keywords to the ad server indicating the topic of the page the ad is to display on. in some cases the ad server system may have analyzed the page content beforehand and assigned it keywords based on that analysis. The ad server uses this information to select an ad that contains matching keywords. This requires that each ad placement is setup with keywords and that each ad has keywords that will match. Contextual targeting is limited because it is targeting based on a single page's context. Contextual targeting is not able to select its audience using parameters beyond general content and page keywords of the current page.